Multi-Protocol Label Switching Transport Profile (MPLS-TP) is a joint International Telecommunications Union (ITU-T)/Internet Engineering Task Force (IETF) effort to include an MPLS Transport Profile (MPLS-TP)within the IETF MPLS architecture to support the capabilities and functionalities of a packet transport network as defined by ITU-T. In the MPLS-TP requirements draft [DRAFT-JENKINS] it is highlighted that an MPLS-TP architecture must allow a smooth migration from legacy networks (e.g. SONET/SDH) to packet transport networks and support, in a reliable way, the accelerating growth of packet-based services (such as VoIP, L2/L3 VPN, IPTV, RAN backhauling, etc.). That migration must be accomplished preserving carriers investments in both Capital Expenditure (CAPEX) and Operational Expense (OPEX) as much as possible. Most of the deployed SDH/SONET networks around the world are based on ring topologies, this assumption being especially true for Metro-Core and Metro-Access networks.
The most interesting applications leading the network transformation are point-to-multipoint (P2MP) applications, such as Internet Protocol Television (IPTV). It is desirable that MPLS-TP supports an efficient solution for P2MP applications over interconnected rings. It is also desirable that these applications have appropriate resiliency, such as recovery from at least a single node/link failure.